Hello Jose,

Yes that was a good point.

Currently I am using 200 microsecond conversion interval and since there was no problem on Ch.1 & 2 I presumed that things are fine. In fact in my case also the Ch.0 setting was kind of imaged on both Ch.3 and 4.

It is possible that my external clock source - a simple 555 - is cranky or unstable or both. OK could not check the waveforms with a scope for want of time.

I think now I will start using the End of Conversion interrupt rather than hard coding the interval.

Thanks for the tip.

Raghu